Silver halide photographic element containing a vinylsulfonyl compound hardener and an acrylic urea as formaldehyde scavenger

ABSTRACT

An acyclic urea aldehyde scavenger is concurrently associated with a hardenable hydrophilic colloid and a vinylsulfonyl hardener. In a preferred form the acyclic urea aldehyde scavenger is incorporated into a hydrophilic colloid layer that is located between a coupler containing photographic layer and an aldehyde source.

United States Patent 1191 Inventors: Robert S. Darlak, Penfield; CharlesJ. Wright, Rochester, both of NY.

Assignee: Eastman Koadak Company, Rochester, N.Y.

Filed: June 27, 1972 Appl. No.2 266,767

US. Cl 96/74, 96/76 R, 96/95;l00;l09;l1l Int. Cl. G03c 1/76, G03c l/48,G03c l/30, G03c l/06,'G03c l/40, G030 l/30 Field of Search 96/111, 55,95, 100, 109, 96/76 R, 74, 22

1111 3,811,891 Darlak et al. I May 21, 1974 SILVER HALIDE PHOTOGRAPHIC[56] References Cited ELEMENT CONTAININ A UNITED STATES PATENTSVINYLSULFONYL COMPOUND HARDENER 3,490,911 1/1970 Burness et al. 96/111AND AN ACRYLIC UR AS 2,579,435 12/1951 Mackey 96/5 6 FORMALDEHYDESCAVENGER 3,168,400 ,2/1965 Blackmer er al 96/56 Primary ExaminerRonaldH. Smith Assistant Examiner-Won H. Louie, Jr. Attorney, Agent, orFirm-M. Carl 0. Thomas [57] ABSTRACT 14 Claims, N0 Drawings SILVERHALIDE PHOTOGRAPI-IIC ELEMENT CONTAINING A VINYLSULFONYL COMPOUNDIIARDENER AND AN ACRYLIC UREA AS FORMALDEI-IYDE SCAVENGER ments byforming on a support one or more photographically active. layers.Typically these photographically active layers contain silver halidedispersed in a hydrophilic colloid, such as gelatin, to form anemulsion. ln multi-layer photographic elements used in color photographythere are at least three selectively sensitive color forming units eachmade up of one or more emulsion layers'coated on one side of aphotographic support, such as film or paper.-The color forming units aretypically rendered variously responsive to the red, green andblue'regions of the spectrum. The blue-sensitive color forming unittypically contains a yellow coupler, the green-sensitive color formingunit amagenta coupler and the red-sensitive color forming unit a c'yancoupler. In an alternative form color couplers are not initially presentin the photographic element, but are introduced during processing afteran imageforming exposure. l-lydrophilic colloid subbing layers,interlayers and over-layers are also typically present. Theblue-sensitive color forming unit forms the outermost unit, and a CareyLea silver filter layer various cyclic and acyclic ureas as aldehydescavengers. Albers et al. U.S. Pat. No. 2,309,492, issued Jan. 26, 1943,points out the problem of traces of formaldehyde causing color-fog inphotographic elements by attacking pyrazolone couplers to produce yellowcompounds and suggests the use of aldehyde scavengers such as hydroxylamines, hydrazine derivatives, hydrazo derivatives, semicarbazides,dimethylhydroresorcin or naphthylene diamines. Callear et al. U.S. Pat.No. 2,895,827, issued July 21, 1959, points to the problem of aldehydemigration from photographic paper supports coated with formaldehyderesins such as ureaformaldehyde and melamine-formaldehyde and'suggestnormally overlies the green and the red sensitive color forming'units toprotect them against residual blue light not absorbed in theblue-sensitive color forming unit. Multi-layer photographic elementsused in color phot'ography of this general type and processes for theirpreparation are well known in the art, as is illustrated,

for example, by Product Licensing Index, Vol. 92, De-

cember 1971, publication 9232, at page 110.

1 It is conventional practice to incorporate into photographichydrophilic colloid layers addenda, referred to as hardeners, having astheir purpose the reduction or elimination. of the susceptibility ofsuch colloid layers to abrasion, swelling in aqueous solutions andsoftening atelevated temperatures. Abrasion is a particular concernduring such fabrication steps as winding and spooling wh'ileswelling andsoftening are of primary concern during processing, especially in thosein-- stances where it is desired to accelerate processing by resort toelevated temperatures.

Aldehydes, such as formaldehyde, glyoxal, succinaldehyde,glutaraldehyde,etc. have been proposed for this purpose. However, certain disadvantageshave been observed by those skilled in the art to result fromassociating aldehydes with photographic elements, even, in someinstances, in the trace amounts found in the atmosph ere. Aldehydes, insome cases, can produce excessive hardening of the hydrophilic colloidcontaining'layers, direct interaction with color couplers, and emulsionfogging.

To combat these disadvantages associated with the presence of aldehydesit has been proposed to utilize the utilization of urea or melaminesizing layers on the surfaceof such supports to act as aldehydescavengers. Blackmer et al U.S. Pat. No. 3,168,400, issued Feb. 2, 1965,teaches that the carrythrough of aldehyde'hardening agents intodeveloping solutions can lead to the formation of sludge and scum andsuggests the incorporation of various amine compounds, including biuret,in

predevelopment baths to scavenge any residual aldehyde hardener thatremains in the emulsion layers before processing. Asano U.S. Pat. No.3,652,278, issued Mar. 28, l972, teaches the use of a variety ofcompounds including amines and amides, such as N,N'-

ethylene urea, acetamide, N,N-diacetylethylene diamine, monomethylamineor dimethylamine as scavengers for formaldehyde gas contained in theatmosphere.

the use of cyclic hydrazide stabilizers and antifoggants in emulsionshardened with ,a mixture of mucochloric acid and formaldehyde to preventinteraction of the hydrazides with the formaldehyde. Jones U.S. Pat. No.2,708,161 and Carroll et al. U.S. Pat. No. 2,708,162, both issued May10, 1965, teach that the use of parabanic acid and urazole,respectively, as antifoggants for polyalkylene oxide sensitizedemulsions interfere with the hardening action of formaldehyde andglyoxal, and the alternative use of alpha-hydroxyadipaldehyde orl,5-bi's(methane sulfonoxy)-pentane as hardeners is suggested. DershU.S. Pat. No. 3,582,346, issued June I, 1971, follows the teachings ofJones and Carroll et al in recognizing that polyalkylene oxidesensitized emulsions are particularly fog sensitive and suggest the useof ethylene diurea as an antifoggant.

The art has recognized distinct advantages to the utilization ofvinylsulfonyl compounds in place of aldehydes as hardeners for thehydrophilic colloid layers of photographic elements. Such compounds arecharacterized by the inclusion of a plurality of vinylsulfonyl groups.In perhaps the simplest possible structural form, divinylsulfone, asingle sulfonyl group joins two vinyl groups. Most typically a pluralityof vinylsulfonylalkyl groups, such as vinylsulfonylmethyl, ethyl, propylor butyl groups, are joined through an intermediate ether, amine,diamine or hydrocarbon linkage. Bis(- vinylsulfonyl) ethers such asbis(vinylsulfonylmethyl) and bis(vinylsulfonylethyl) ethers have beenfound particularly suitable for use as hardeners. Representativevinylsulfonyl hardeners as well as procedures for their synthesis anduse are disclosed in Bumess et'al. U.S. Pat. Nos. 3,490,911, issued Jan.20, 1970; 3,539,644,

issued Nov. 10, 1970, and 3,642,486, issued Feb. 15, 1972, thedisclosures of which are incorporated by reference.

In one aspect, the present invention is directed to a process wherein avinylsulfonyl hardener and an acyclic urea aldehyde scavenger areconcurrently associated within a hydrophilic colloid forming a portionof a photographic element. In an additional aspect, this invention isdirected to a photographic element having a hydrophilic colloid layercontaining a vinylsulfonyl harde'ner and an acyclic urea scavenger.

As utilized herein the term an acyclic urea refers to those compounds inwhich none of the urea moieties HN E NH present form a portion of a ringstructure, as is the case, for example, in compounds such as barbituricacid and urazole. It is contemplated that these acyclic ureas caninclude one or more cyclic nitrogen substituents, as is hereinafter morefully illustrated.

It has been discovered that vinylsulfonyl hardeners and acyclic ureaaldehyde scavengers are compatible in the hydrophilic colloid layers ofphotographic elements. This is quite unexpected, since both cyclic andacyclic amides, including ureas, having been generally known in the artto be directly reactive with aldehyde hardeners for hydrophilic colloidlayers. To further illustrate the unexpected characterof this discoveryit is noted that the behavior of acyclic urea aldehyde scavengers incombination with vinylsulfonyl hardeners differs from the behavior ofheterocyclic ureas, such as N,N-ethylene urea, barbituric acid andurazole. Vinylsulfonyl hardeners incorporated in hydrophilic colloid.

layers containing one of these heterocyclic ureas are reactive with theheterocyclicurea in preference to the hydrophilic colloid, to thedetriment of both the hardening and aldehyde scavenging propertiesdesired to be imparted by these addenda.

lt is a distinctly advantageous feature of this invention that thevinylsulfonyl hardener and acyclic urea aldehyde scavenger can beconcurrently associated with a hydrophilic colloid layer of aphotographic element. This means simply that the colloid, the acyclicurea aldehyde scavenger and the vinylsulfonyl hardener (as opposed tothe scavenger and the reaction product of the vinylsulfonyl hardenerwith the colloid) can be brought together. This permits both addenda tobe introduced into or on the colloid in a substantially contemporaneousmanner during formation of the photographic element, rather than waitinguntil the vinylsulfonyl compound has hardened the hydrophilic colloid tothe extent desired before incorporation of the aldehyde scavenger intothe element. The full extent of this advantage can be better appreciatedwhen it is considered that in forming a photographic element a number ofhydrophilic colloid layers can be advantageously concurrently formed ona support and that the vinylsulfonyl hardener, even if it is initiallypresent within only one of these layers, can distribute itselfthroughout the layers, as is taught more fully by Graham French Pat.2,090,921, issued Dec. 20, 1971. Additionally, the acyclic ureascavenger when non-ballasted can also wander from its situs ofintroduction in the photographic element. Utilizing an aldehydescavenger which is incompatible with the vinylsulfonyl hardener in thiscircumstance requires a subsequent preparation step to associate thisaddenda with a hydrophilic colloid layer.

Since hydrophilic colloids employed in the formation of photographicelements frequently contain water as one ingredient at the time they aredeposited as layers on a support, it is preferred to utilize watersoluble acrylic urea aldehyde scavengers. Preferred acyclic ureascontemplated for use in the practice of this invention are aldehydescavengers having the formula:

wherein m O A.. O a

H 8 11 X is a HN-(OHz)mN or HN- group;

m is l or 2; n is 0 or 1; and R and R are independently selected fromthe class consisting of hydrogen, lower alkyl, hydroxyalkyl and aryl,such as a phenyl substituent. As utilized herein the term lower alkyl"refers to those alkyl groups having six or fewer carbon atoms. Exemplarywater soluble acyclic ureas within the contemplation of this inventioninclude urea, methyl urea, ethyl urea, butyl urea, hexyl urea,N,N'-dimethyl urea, N,N'-diethyl urea, hydroxymethyl urea,N,N-di(2-hydroxyethyl) urea, N,N'-di(2- hydroxyhexyl) urea, phenyl urea,biuret, hydroxyethyl biuret, l,5-di(hydroxyethyl) biuret, methylenediurea, l,l-ethylene diurea, and- 3,3'-dihydroxyethyl-l ,1- ethylenediurea. While it is preferred to utilize water soluble ureas, it isrecognized that photographic addenda are frequently incorporated usingother solvents. lt is accordingly contemplated that any acyclic ureaaldehyde scavenger known to be useful in photographic elements can beemployed.

In one form of the invention the acyclic urea scavenger can beincorporated within the vinylsulfonyl hardener containing hydrophiliccolloid layer of the photographic element to be protected from aldehydeattack. Thus in an exemplary simple form a photographic elementaccording to this invention can comprise a support having thereon asingle silver halide photographic emulsion layer containing ahydrophilic colloid, an acyclic urea aldehyde scavenger and avinylsulfonyl hardener. Since most photographic elements contain aplurality of hydrophilic colloid layers, it is generally preferred tomaximize the protection of the photographic element by locating thealdehyde scavenger in a hydrophilic colloid layer between the aldehydesource and the layer to be protected from aldehyde attack. Where thesupport for the photographic element is itself penneable to or a sourceof aldehydes, the aldehyde scavenger may be located beneath the layer tobe protected or may be located both under and over the layer to beprotected, as in a colloid subbing layer, interlayer, overcoat layer, ora combination of such layers. In most instances photographic supportssuch as polymeric films, glass, metal and the like are impermeable toaldehydes and it is only necessary to protect the photographic elementfrom aldehyde incursion through the overcoat. In a typical colorphotographic element having a film support in which it is desired toprotect the magenta and/or cyan coupler conv taining layers fromaldehyde attack, the scavenger is preferably located in the outerhydrophilic colloid layer or the Carey Lea silver filter layer, but canbe advantageously incorporated in any overlying layer or interlayer,including a blue-sensitive emulsion layer. It is recognized that thealdehyde scavenger need not be blended into a vinylsulfonyl hardenerhydrophilic colloid layer to be associated therewith as contemplated bythis invention, but can simply contiguously overlie the hardenercontaining hydrophilic colloid layer.

The concentration of acyclic ureaaldehyde scavengerassociated with aphotographic element according to this invention can vary widely,depending upon such factors as the degree of protection from aldehydeattack desired, the concentrations of aldehyde expected to beencountered, the sensitivity of the ingredients within the photographicelement sought to be protected, the water solubilityof the acyclicureachosen and the like. In order to effectively protect photographicelementsfrom visible degradation attributable to attack by formaldehydepresent in the atmosphere during storage it is generally preferred thatthe acyclic urea be present in a concentration of at least 0.1milligrams per square decimeter. Generally acyclic urea concentrationsof from 0.1 to 40 milligrams per square decimeter are preferred withconcentrations of from 1 to. 30 milligrams per square .decimeter beingparticularly useful. The vinylsulfonyl hardener associated with theacyclic urea aldehyde scavenger can be incorporated in any conventionaluseful concentration and will typically be employed in a concentrationof from 0.1 to 10 percent and, most commonly 0.5 to 6.0 percent, byweight, based on the weight of the hardenable material present. I

Most commonly, gelatin constitutes the hardenable material presentwithin the hydrophilic colloid layers of photographic elements. Othermaterials known to be hardenable by vinylsulfonyl hardeners which may bepresent in one or more hydrophilic colloid layers of a photographicelement-are colloidal albumin, acid or water-soluble vinyl polymers,cellulose derivatives, proteins, various polyacrylarnides, dispersedpolymerized vinyl compounds, particularly those which increase thedimensional stability of photographic materials exemplified byamine-containing polymers of alkyl acrylates,

methacr'ylat es, acrylic acid, sulfoalkyl acrylates or methacrylat'es orthe like. One function of the acyclic urea aldehyde scavengers of thisinvention can be to protect such hardenable materials from furtherhardening by aldehydes after the desired degree of hardening has beenimparted by the vinylsulfonyl hardener.

Another function of the acyclic urea aldehyde scavenger can be toprotect one or more other ingredients of a photographic element. Forexample, the acyclic urea-aldehyde scavenger can be used to protectfixed color couplers, such as those which are reactive with arylamines,which can be present in one or more of the color forming units ofa photographic element. Certain of these couplers are quite sensitive tothe presence of aldehydes and, if left unprotected, during storagebetween preparation and processing, will readily react with formaldehydepresent in the atmospheres to produce a compound visibly distinguishablefrom the compound desired to be formed by reaction of the coupler withthe aryl amine developer. In the reaction of a fixed coupler containedin a photographic element with an aldehyde a marked color loss canoccur. For example, magenta couplers such as S-pyrazolone couplers asdescribed in Loria et al. U.S. Pat. No. 2,600,788, issued June 17, 1952,are known to suffer marked color loss when associated with relativelysmall quantities of aldehydes.

Photographic elements utilizing non-ballasted couplers such as thoseadded during development are protected from color loss by protecting thecolloid layers from undesirable hardeningthat can retard or impedeintroduction of these couplers. Accordingly, it is apparent that thisinvention is applicable to color photographic elements generally and isspecifically noted to be useful in protecting photographic elements forproducing both positive and reversal color images. Exemplary colorphotographic elements capable of being benefited by the practice of thisinvention are set forth in Graham et al. U.S. Pat. No. 2,725,292,Salminen et al. U.S. Pat. No. 2,895,826, Bush et al. U.S. Pat. No.2,920,961, Beavers U.S. Pat. No. 2,983,608, Loria et al. U.S. Pat. No.3,006,759, Whitmore et al. U.S. Pat. No. 3,l48,062,-Loria et al. U.S.Pat. No. 3,214,437, Barr et al. U.S. Pat. No. 3,227,554, Young U.S. Pat.No. 3,419,391and Lestina U.S. Pat. No. 3,519,429.

This invention can be further illustrated by the following examples ofpreferred embodiments thereof although it will be understood that theseexamples are included merely for purposes of illustration and are notintended to limit the scope of the invention unless otherwise indicated.

EXAMPLE 1 containing a magenta-dye-forming coupler, which was in thiscase a S-pyrazolone coupler'as disclosed by Loria et a1, cited above; ayellow Carey-Lea silver gelatin filter layer; a blue-sensitive silverhalide emulsion layer containing a yellow-dye-forming coupler; and agelatin outerlayer containing the scavenging compound andbis(vinyl-sulfonylmethyl) ether hardener. The hardener was incorporatedin the outerlayer to diffuse through and harden each of the gelatinlayers present at a concentration of 1.5 percent by weight based on thegelatin present. One of the photographic elements served as a controland contained no aldehyde scavenger; the second element contained 3mg/dm of barbituric acid; and the third element 5 mg/dm of 1,1- ethylenediurea. The scavengers were prepared as an aqueous solution for blendingwith the gelatin prior to forming the layers.

Each of the photographic elements was given a sensitometric exposure andthen exposed to an aldehyde by suspension for 16 hours in a stream ofroom temperature air having a relative humidity of from 50 to 60 percentand containing from 0.4 to 0.8 mg of gaseous formaldehyde'per liter ofair. After exposure to aldehyde the elements were immersed at 38C. for 3minutes in Kodak F-6 developer, for 6 minutes in bleach-fix solutioncomprised of a ferric ethylene diamine te'tracetic acid and ammoniumthiosulfate, for minutes in water and finally for 10 seconds in astabilizer bath comprised of 6 ml of 35 percent formalin and 8 to 9 mlof an ethylene oxide wetting agent per liter.

Even though the photographic elements were processed at relatively lowtemperatures the emulsion layers were lost from the barbituric acidcontaining photographic element during processing. This indicated thatthe barbituric acid had reacted directly with thebis(vinylsulfonylmethyl) ether so that the emulsion layers wereinadequately hardened to permit processing. In the remaining twophotographic elements the relative maximum densities of the magentaimage forming dyes contained in the initially green-sensitive emulsionlayer of each photographic element were compared to determine theeffectiveness of the 1,1 -ethylene diurea as an aldehyde scavenger.Whereas the element containing no aldehyde scavenger exhibited a 57percent dye loss, the 1,1 '-ethylene diurea protected element exhibitedonly a 30 percent dye loss under the stringent conditions of comparison.Percentage dye loss attributable to aldehyde attack wasin each instancedetermined by comparison with an identical photographic elementidentically exposed and processed, but not subjected to aldehydeexposure. The fact that the emulsion layers remained on the photographicelement containing the l,l T-ethylene diurea during processing indicatedthat the bis(vinylsulfonylmethyl) ether had effectively hardened thegelatin layers and had not preferentially interacted with the acrylicurea aldehyde scavenger. This was corroborated by comparing the swellingof the acyclic urea containing photographic element with that of theelement free of aldehyde scavengers.

EXAMPLES 2-7 The procedures of Example 1 were repeated usingl,l-ethylene diurea and varying the concentration and location of thescavenger. The results are set forth in Table I.

Carey Lea Silver Layer EXAMPLES 8-16 A number of photographic elementswere prepared differing only by the choice of aldehyde scavenger, eachphotographic element comprised a support impermeable to aldehydes onwhich was deposited a gray silver gelatin emulsion layer; aphotographically active layer containing 28.5 mg/dm silver bromide, 24.5

mg/dm gelatin and 9.5 mg/dm of the magenta dyeforming coupler of Example1; and an overlayer comprised of 8.0 mg/dm of gelatin having dispersedtherein 7.0 mg/dm of aldehyde scavenger and sufficientbis(vinylsulfonylmethyl) ether to adequately harden each of the gelatinlayers present. The image exposure, aldehyde exposure and processingwere carried out as described in Example 1. The specific aldehydescavengers incorporated and the percentage of magenta dye loss are setforth in Table ll.

No evidence was apparent of interaction of the vinylsulfonyl hardenerand the aldehyde scavenger, and in every instance the aldehyde scavengereffectively reduced the percentage of dye loss attributable to aldehydeattack.

The invention has been described with particular reference to certainpreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention as described above and as defined in the appended claims.

We claim:

1. In a silver halide emulsion containing photographic element in whicha vinylsulfonyl hardener is associated with a hydrophilic colloid layer,the improvement in which said hydrophilic colloid layer contains inaddition to said vinylsulfonyl hardener an acyclic urea aldehydescavenger in an amount of at least 0.1 milligrams per square decimeter,said scavenger having the formula:

wherein:

m is l or 2;

n is 0 or 1; and

R and R are independently selected from the class consisting ofhydrogen, alkyl containing one to six carbon atoms, hydroxyalkyl andaryl.

2. In a silver halide emulsion containing photographic element in whicha vinylsulfonyl hardener is associated with a plurality of superimposedhydrophilic colloid layers on a support which is substantiallyimpenetrable by formaldehyde and in which at least one of said layerscontains a coupler capable of reacting with an aryl amine to produce afirst compound having a visible color and, alternatively, capable ofreacting with formaldehyde to produce a second compound visiblydistinguishable from the first compound, the improvement comprising atleast one of said hydrophilic colloid layers overlying said formaldehydereactive coupler containing layer including an acyclic urea formaldehydescavthe further improvement in which 9 enger in an amount of at least0.] milligrams per square decimeter, said scavenger having the followingstructural formula:

wherein Rand R are independently selected from the class consisting ofhydrogen, alkyl containing one to six carbon atoms, hydroxyalkyl and aphenyl substituent.

3. In a photographic element according to claim 2, the furtherimprovement in which said scavenger ,is present in an amount of from 1to 30 milligrams per square decimeter.

4. In a photographic element according to claim 2, the furtherimprovement in which said scavenger is urea.

5. In a photographic element according to claim 2, the furtherimprovement in which said scavenger is an aryl substituted urea.

6. In a photographic element according to claim 2, the furtherimprovement in which said scavenger is phenyl urea.

7. In a photographic element according to claim 2, the furtherimprovement in which said scavenger is an alkyl substituted urea.

8. In a photographic element according to claim 2, said scavenger is adialkyl urea. I

9. In a photographic element according to claim I, the furtherimprovement in which said scavenger is biuret.

10. In a photographic element according to claim 1, the furtherimprovement in which said scavenger is an alkylene diurea.

11. In a photographic element according to claim 1, the furtherimprovement in which said scavenger is ethylene diurea.

12. In a photographic element according to claim 2, the furtherimprovement in which said hardener is a bis(vinylsulfonyl) ether.

13. In a photographic element according .to claim 2, the furtherimprovement in which said hardener is bis(vinylsulfonylmethyl) ether.

14. In a silver halide emulsion containing photographic elementcomprising a plurality of bis(vinylsulfonyl) hardener containing gelatinlayers located in superimposed relationship on a support which issubstantially impenetrable to formaldehyde and in which said layers format least three color forming units each sensitive to a different regionof the visible spectrum, one of which units contains a S-pyrazolonecoupler, the improvement comprising at least one of said gelatin layersoverlying said 5- pyrazolone coupler containing layer comprising aconcentration of ethylene diurea of at least 0.1 milligrams per squaredecimeter.

2. In a silver halide emulsion containing photographic element in whicha vinylsulfonyl hardener is associated with a plurality of superimposedhydrophilic colloid layers on a support which is substantiallyimpenetrable by formaldehyde and in which at least one of said layerscontains a coupler capable of reacting with an aryl amine to produce afirst compound having a visible color and, alternatively, capable ofreacting with formaldehyde to produce a second compound visiblydistinguishable from the first compound, the improvement comprising atleast one of said hydrophilic colloid layers overlying said formaldehydereactive coupler containing layer including an acyclic urea formaldehydescavenger in an amount of at least 0.1 milligrams per square decimeter,said scavenger having the following structural formula:
 3. In aphotographic element according to claim 2, the further improvement inwhich said scavenger is present in an amount of from 1 to 30 milligramsper square decimeter.
 4. In a photographic element according to claim 2,the further improvement in which said scavenger is urea.
 5. In aphotographic element according to claim 2, the further improvement inwhich said scavenger is an aryl substituted urea.
 6. In a photoGraphicelement according to claim 2, the further improvement in which saidscavenger is phenyl urea.
 7. In a photographic element according toclaim 2, the further improvement in which said scavenger is an alkylsubstituted urea.
 8. In a photographic element according to claim 2, thefurther improvement in which said scavenger is a dialkyl urea.
 9. In aphotographic element according to claim 1, the further improvement inwhich said scavenger is biuret.
 10. In a photographic element accordingto claim 1, the further improvement in which said scavenger is analkylene diurea.
 11. In a photographic element according to claim 1, thefurther improvement in which said scavenger is ethylene diurea.
 12. In aphotographic element according to claim 2, the further improvement inwhich said hardener is a bis(vinylsulfonyl) ether.
 13. In a photographicelement according to claim 2, the further improvement in which saidhardener is bis(vinylsulfonylmethyl) ether.
 14. In a silver halideemulsion containing photographic element comprising a plurality ofbis(vinylsulfonyl) hardener containing gelatin layers located insuperimposed relationship on a support which is substantiallyimpenetrable to formaldehyde and in which said layers form at leastthree color forming units each sensitive to a different region of thevisible spectrum, one of which units contains a 5-pyrazolone coupler,the improvement comprising at least one of said gelatin layers overlyingsaid 5-pyrazolone coupler containing layer comprising a concentration ofethylene diurea of at least 0.1 milligrams per square decimeter.